Univ., FB Biologie, Diss.--Hamburg, 1999. / Literaturverz. S. 116 - 126.

No description available.

Zugl.: Hannover, Universiẗat, Diss., 2008. / Auch als: Deutsche Geodätische Kommission bei der Bayerischen Akademie der Wissenschaften : Reihe C, Dissertationen ; 622.

München, Techn. Univ., Diss., 2002. / Computerdatei im Fernzugriff.

München, Techn. Univ., Diss., 2002. / Computerdatei im Fernzugriff.

Zugl.: Kiel, University, Diss.

München, Techn. Universiẗat, Diss., 2002.

University, Diss., 2004--Kiel.

Resumo: Considerando-se as constantes mudanças que vêm ocorrendo no cenário de distribuição de energia elétrica, devido ao grande avanço da eletrônica de potência e cargas não lineares instaladas no sistema, fazem-se necessários estudos para diagnosticar como e quanto essas mudanças podem estar afetando os equipamentos instalados nas redes de distribuição. A proposta deste trabalho é a análise da influência de harmônicos e desequilíbrios nos erros de medição de energia elétrica ativa em medidores de energia tipo indução, classe de precisão 2%. Estes equipamentos são normalmente projetados para atuarem com condições ideais de freqüência constante, formas de onda de tensão e corrente senoidais e sistema equilibrado. Condições estas, que não são a realidade das redes de distribuição de energia elétrica. Para a realização da análise dos equipamentos selecionados, submetidos aos efeitos das componentes harmônicas nas tensões e correntes, inclusive desequilíbrios de tensões, montou-se um arranjo padrão de medição, onde foram ensaiados os medidores submetidos à estes distúrbios, sob as mesmas condições laboratoriais, considerando-se três repetições para cada amostra selecionada. As distorções harmônicas de tensões e correntes, admitidas para ensaios, foram obtidas por medições em consumidores em... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Considering the constant changes that have been occurring in the electric energy distribution scenery, due to the great improvements of the power electronics devices and non linear loads installed in the system, there are several studies developed in order to analyze and diagnosis the effects of these changes, and how much these loads affect the equipments installed on the distribution systems. The proposal of this research is to analyze the influence of harmonic contents and voltage unbalances in the systems on the measurement errors of the active electric energy using the induction watt-hour meters, with accuracy of 2%. These equipments are usually designed to operate in ideal conditions with constant frequency, sinusoidal voltage and current waveforms, and balanced system. However, these conditions are not the reality of the electric energy distribution systems. The procedures for the measurements, considering the selected samples of the induction watt-hour meters under influence of current and voltage harmonic contents, and voltage unbalances, were based on a measurement set-up established for testing, in the same conditions, all the selected samples considering its three repetitions. The harmonic voltage and current contents, admitted for testing, were obtained by measurements in consumers with different load... (Complete abstract click electronic access below) / Orientador: Carlos Alberto Canesin / Coorientador: Flávio Alessandro Serrão Gonçalves / Banca: Luis Carlos Origa de Oliveira / Banca: Fernando Luiz Marcelo Antunes / Mestre

A digital statistical watthour meter which operates by polarity-coincidence correlation is proposed. The output represents a continuously 'up-dated', time-multiplied estimate of the current and voltage cross-correlation function for zero delay. In previous correlators of this type, bounded uniformly-distributed random noise has been added to each input before clipping to linearize the input/output correlation function relationship. In the work reported here, the noise sources have been replaced by deterministic triangular wave generators. These have the advantage of being much simpler to construct and of enabling the statistical watthour meter to produce an acceptable estimate of the energy (for certain types of inputs) more quickly than with the former type of auxiliary function generator. An attempt has been made to predict the performance of the device using deterministic auxiliary functions by means of both analogue and digital computer simulations„ A prototype has also been constructed and tested with d-c and a-c inputs. The results of the simulations and prototype tests suggest that, if the meter electronics were refined and constructed for the most part as an integrated circuit, the statistical watthour meter could become a practical energy-measuring device in domestic, industrial and laboratory applications. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate